The in vitro cultivation or culturing of eukaryotic cells is well known. Presently, repositories for cell cultures world wide contain more than 5,000 different eukaryotic cell types which may be grown in vitro in appropriately selected liquid media. The European Collection of Cell Cultures (ECACC), for example, maintains cultures of more than 50 cell types from over 40 species. Many other eukaryotic cell lines available to investigators are listed in the catalogues of the ATCC American Type Culture Collection, DCTDC Tumor Repository, DSMZ Human and Animal Cell Cultures, ICLC Interlab Cell Line Collection, Istituto Giannina Gaslini, IZSBS Istituto Zooprofilattico Sperimentale and NIA National Institute of Aging Cell Repository.
Cell culture is a powerful approach originated over a century ago to study the behavior of different cells under physiological conditions as well as stress. In vitro cell culture is greatly influenced by an environment that favors the spreading, migration and proliferation of cells. The cell culture environment includes: the nature of the substrate or phase on or in which cells grow that may be a solid surface, as in monolayer growth, or a liquid, as in a suspension culture; the physiochemical and physiological composition of the medium; the constitution of gas phase; and the incubation environment, including temperature and humidity. A wide variety of liquid media suitable for the maintenance and growth of mammalian cells for in vitro culture have been formulated and are commercially available.
Conventional cell culture cannot be performed in the absence of a cell culture facility staffed by well-trained and experienced personnel. In addition, conventional methods require removal of a cryoprotectant from cryopreserved cells upon cell revival. This removal of cryoprotectant (e.g., DMSO, glycerol) from cryopreserved cells involve multiple. steps and is usually performed by an experienced personnel. As soon as cryopreserved cells ate thawed 37° C., they are carefully transferred drop wise into a 10 ml centrifuge tube containing Hanks balanced salt solution or phosphate buffered saline. This gradual dilution process is particularly important when DMSO is used as the cryoprotectant, with which sudden dilution can cause severe osmotic damage and reduce cell survival. The 10 ml tube containing cells is centrifuged at 230 g for 4:30 minutes. The DMSO in the supernatant is aspirated and the cells are recovered and transferred to the cell culture flask in the presence of prewarmed growth medium which is conventionally prewarmed at 37° C. for 15 minutes prior to cell culture. The cell culture flask is kept at 37° C. in a CO 2 incubator, and cell growth and viability are observed. Therefore, it would be useful to the industry to have a system for performing cell culture that does not require well-trained and experienced personnel.
Further, it would be advantageous to perform cell cultures without the need to remove cryoprotectant upon cell revival. Therefore, due to the enormous applicability and utility of cell culture in biology, it is desirable to have a self-contained system capable of performing cell culture without human manipulation. The present invention addresses these needs by providing a completely self-contained cell culture system that can be stored for extended periods of time. When required, this system may be thawed and incubated at the desired temperature to carry out cell culture without the need to remove the cryoprotectant.